Inserted tooth for saws.



S. 1. BROWN. INSERTED TOOTH FOR SAWS. APPLICATION FILED Aus.4. .1913.

1,140,021. Famed M1y18, 1915.

INl/E/VTOR ,S'amueldlfirowm WITNESSES:

THE NORRIS PETERS C0,, PHGTO-LITHQ. WASHINGTO. D. C

SAMUEL J. BROWN, 0F VANCOUVER, BRITISH COLUMBIA, CANADA, A SSIGNOR OF ONE- HALF T0 ZIBEA GIBERSON, OF VANCOUVER CANADA.

INSERTED TOOTH FOR SAWS.

Specification of Letters Patent;

. Patented May 18, 1915.

Application filed August 4, 1913. Serial N 0. 782,905. 1

a citizen of the Dominion of Canada, resid ing at Vancouver, in the Province of British Columbia, Canada, have invented certain new and useful Improvements in Inserted Teeth for Saws, of which the following is a specification. V

This invention relates to an inserted tooth for a circular saw, the object of the device being to positively and securely hold the cutting tooth or bit in the saw blade by its locking piece, whereby, being so securely held, the cutting face of the tooth may with safety have a greater pitch than is usual, with the subsequent greater efiiciency of cut. The design also enables an ample gullet to be provided for the reception of the sawdust from the increased feed of out possible.

The invention further comprises a simplification in the form of both cutting bit and locking piece, rendering them cheaper to make and less subject to wear or injury, and the looking piece being free from the usual complication of fastening, may be made symmetrical so that it is reversible in its application to secure the cutting bit.

The construction by which these results are attained is particularly set forth in the following specification, reference being made to the drawings by which it is accompanied, in which:

Figure 1 represents a portion of a saw blade embracing the space of three teeth.

Fig. 2 is a perspective view of a portion of a saw blade with the invention applied. Fig. 3 is a section on the line A in Fig. 1, and Fig. 4 is a face or edge view of one of the cutting bits detached from the blade.

In these drawings 2represents a portion of the saw blade in which is provided a seat 7, 8 and 5 for the reception of the tooth or cutting bit 3, and at 6 a seat for the locking piece 4. The seat 60f the lockingpiece in the blade is an uninterrupted circular arc, and that for the cutting bit 3 is concentric with 6 and outside of it.

The edge of the locking piece seat 6 is V beveled from both sides ofthe blade to fit a corresponding V groove on the edge of the locking piece 4, and the upper and greater part 7 of the cutting bit seat has a corresponding V bevel, which bevel portion 1s removed to form the seat 8 for the lower end of the shank of the cutting bit so that a square shoulder 10 is oflered between 7 and8.

The cuttingbit 3 is shaped as shown in the drawing, the upper part of the seat in the blade having a V groove to fit the bevel edge 7 and'thisV groove ends in a square shoulder at 10 and the end of the bit shank is carefully fitted against the square edge of the saw blade at Sand 5.

The inner side'll of the shank of the cutting bit is curved to the same radius, and

is concentric with the seat 6 of the locking piece, and for aboutItwo-thirds of its in; serted length from the bottom end is V beveled tofit the V groove of the locking piece 4. At'the termination of this V bevel the bit is carried around the end 12 of the.

locking piece and between here and the cutting face of the bit the inner side of the bit is hollowed out, as at 9, in a, manner to direct the flow of the sawdust that it will not impinge on the end joint of the locking piece on the bit.

The locking piece 4, by which the cutting bit 3 is secured in position, is formed as a symmetrical crescent, the outer edge of which'conforms to the are 6 of the recess 'provided for it in the blade andhas the usual V groove to fit the V edge of that are and the V edge 11 of that portion ofthe bit 3 which is concentric with 6.

I To retain the sawdust, in the gullet of each tooth during the cut through thelog andprevent it from passing down the sides of the blade 2 of the saw, where it might produce undue friction, the thickness of the cutting bit 3 is increased along the inner edge 9 and as far as theshoulder against which the end 12 of the locking piece bears, and the thickness of the locking piece at the ends 12 is similarly increased, the increase of thickness being carried around the inner edge of the'crescent in'a border 13 which gradually lessens in depth toward the midlength of the bit, as shown in the drawing. This increase of thickness along the inner edge 9 of the bit and of the locking piece not only serves the object for which it was introduced, but strengthens the cutting bit 3 and locking piece 4 where such increase is needed enabling an effective hollow at 9 and a larger gullet to be provided with the required strength of'these parts.

In a number eight gage saw the thickness of the body of the locking piece would be about No. 7 gage and the thickness along the swaged portion 13 would be No. 4L gage.

So constructed, the bit is inserted in its seat 7 8 and 5, and the locking piece a is inserted in its seat 6, as shown in the middle of Fig. 1. To secure the cutting bit 3, the locking piece is rotated in the direction of the arrow to the position shown on the right of Fig. 1, and the shank of the cutting bit is firmly held in its seat in the saw blade by engagement of the adjacent end of the looking piece with the inner side 11 of the shank of the bit.

With this manner of attachment. the shank of the cutting bit is positively and securely held in its seat in the blade 2 of the saw. It is strongly held against lateral movement by engagement of the bevel edge of the blade in the V groove of the bit on one edge, and by engagement of the bevel edge 11 of the bit in the V grooveof the locking piece 4, which is itself securely held by engagement of its V groove on the beveled edge of the seat 6. The tooth cannot move outward because of engagement with the square shoulder 10 of the bit seat in the blade, and bottoms firmly on the end seat 5.

Being so securely held the tooth may be placed in the blade to have a greater pitch than is usual, and has therefore a greater cutting eiiiciency.

Experience with this cutting bit has shown that the locking piece does not, in use, move backward from its holding position and it is therefore unnecessary to provide a means for securing the locking piece in the locked position. It may, therefore, be formed symmetrical in its outline, thus enabling it to be reversible in its application to secure the bit.

The advantages of having a reversible locking piece are manifest, in that the life of the locking piece is thereby doubled and there is a further economy in the less cost of manufacture, as the locking piece is without complication of any kind and does not require any supplementary fitting or machining beyond the milling of the circumferential groove.

The tooth has been subjected to practically destructive tests and no work that has been imposed upon it has been able to injure.

or dislodge it and where it has encountered hard foreign matter, such as a stone embedded in a soft cedar log, where a rapid rate of feed has been used, teeth have been broken without injury to the blade and the work has been resumed by the insertion of new teeth.

Having now particularly described my in vention, I hereby declare that what I claim or cutting bit having a shank the inner end outer sides of which are concentric curves said bit being inserted in a recess provided for it in the blade at an angle to afford the maximum pitch desired, and a locking piece the outer side of which is a circular are which corresponds with the inner side of the cutting bit shank, said locking piece fitting a recess provided for it in the blade of the saw and susceptible of rotation from that recess up the shank of the cutting bit the tooth or cutting end of the bit being laterally enlarged to overhang and protect the end of the locking piece.

3. An inserted tooth for saws, comprising the combination with a saw blade, of a tooth or cutting bit having a shank and a cutting head, the inner and outer edge faces of the shank being formed as concentric curves, said blade having a bit receiving recess, and having a locking piece receiving recess, a locking piece inserted in the locking piece recess, the outer edge face of said locking piece being a circular arc corresponding with the inner edge face of the cutting bit shank and susceptible of rotation in its recess up the shank of the cutting bit, the head of said cutting bit being laterally enlarged to overhang the end of said locking piece and protect the same, and the outer edge face of said cutting head being concaved above the plane of contact with the locking piece end, said locking piece having at its outer or exposed edge, on each side of the blade, lateral projections conforming in thickness substantially to the thickness or width of the contacting portion of the cutting head of the bit, substantially as shown and described.

4. An inserted tooth for saws, comprising the combination with a saw blade having suitable recesses cut for the reception of the cutting bit and its locking piece, the recess for the locking piece being a circular arc and that for the cutting bit a circular are outside of and concentric with that for the locking piece, of a cutting bit having a shank the outer and inner sides of which are concentric arcs conforming to those of the cutting bit and locking piece recesses, the inner side of the cutting bit on the front or face side being carried forward to project over the end of the locking piece when in position 7 cutting bit having a shank and a shouldered cutting head, the inner and outer sides of the shank being formed as concentric curves, said blade having a bit receiving recess, and having a locking piece receiving recess, a locking piece, the outer side of said locking piece being a circular arc corresponding with the inner side of the cutting bit shank and susceptible of rotation in its recess up the shank of the cutting bit to engage the shoulder of the cutting head.

6. The combination with a saw blade having a bit receiving recess and a locking piece receiving recess, of a cutting bit having a shank and a cutting head, said'cutting head being offset to provide a shoulder, a locking piece inserted in the locking piece recess to engage the shank of said cutting bit and abut said shoulder, said locking piece having its exposededge curved in the arc of a circle, said cutting head having its front face concaved, the center of curvature of said front face being differently located from the center of curvature of said exposed edge of said locking piece, whereby to direct the flow of sawdust away from the contact- Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

ing faces of the locking piece and bit head the contacting faces of the locking piece and bit head lying in a plane making an acute angle with the front exposed edge of the bit.

7. The combination with a saw blade having a bit receiving recess and a locking piece receiving recess, of a cutting bit having a shank and a cutting head, said cutting head being offset toprovide a shoulder, a locking piece inserted inthe locking piece recess to engage the shank of said cutting bit and abut said shoulder, said locking piece hav-v ing its exposed edge curved in the arc'of a circle, said cutting head having its front' face concaved, the center of curvature of said front face being differently located from the center of curvature of said exposed I edge of said locking piece, whereby to direct the flow of sawdust away from the contacting faces of the locking piece and bit head, said bit head being of greater width than the width of said shank, the contacting faces of the locking piece and bit head lying in a plane making an acute angle with the front exposed edge of the bit substantially as shown and described. In testimony whereof I aflix my signature in presence of two-witnesses.

i SAMUEL J. BROWN Witnesses:

ROLAND BRITTAIN, MAY WHYTE.

Washington, D. 0. 

